The present invention relates to a device for controlling a heater or warmer for automobiles for transporting foods, chemicals, and the like while keeping them warm.
Automobiles for transporting foods, chemicals, and the like while keeping them warm require a heat source. Japanese Laid-Open Patent Publication No. 61-211118 discloses a burner device as such a heat source for use with a heater or warmer for an aubomobile, the burner device comprising a burner for combusting fuel, a heat exchanger for recovering heat generated by the burner, and a controller for controlling the fuel combustion in the burner in response to the temperature detected in a heating or warming container.
Automobiles with heating or warming containers, especially those for delivering food early in the morning, should preferably be loaded with food in the previous night because no loading process will be required in the next morning. To do so, the heater or warmer should be continuously operated throughout the night. However, since the conventional heater including a burner is energized by a battery on the autombile, the heater cannot be continuously kept in operation due to the limited capacity of the battery.
One attempt to solve the above problem, the inventor has led to an automotive heating or warming container which, as disclosed in Japanese Patent Application No. 60-299344, comprises a burner for combusting fuel, a heat exchanger for recovering heat generated by the burner and introducing heated or warm air into the heating container, a controller for controlling the heated air to be supplied to the heating container based on a temperature signal from a temperature sensor located in the heating container, and a voltage control unit for converting the voltage of a commercial electric power supply to a voltage equal to that of a battery mounted on the automobile. While the automobile is running, the above various components are energized by the battery, and while the automobile is at rest, the components are energized by the commercial electric power supply.
The burner includes an atomizing glow plug for heating and atomizing fuel and an igniting glow plug for igniting the fuel as atomized by the atomizing glow plug. Since the atomizing and igniting glow plugs should be supplied with a large electric current, the voltage control unit requires, as a voltage converter, a transformer and a rectifier which are of a large current capacity. Therefore, the control device for the heating container is large in size and expensive to manufacture.